Pressure-gage.



L. L. TATUM.

PRESSURE GAGE. APPLICATION FILED 111111.25, 1911.

l, 1 1 9, 203, Patented Dec. 1, 1914.

2 SHEETSSHBET 1.

L. L. TATUM.

PRESSURE GAGE.

APPLIOATIOH 31mm 11136.25, 1911.

Patented Dec.1,1911

UNITED STATES PATENT onnron.

LEWIS L. TATUM, F MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER-HAMMERMFG. COL, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

PRESSURE-GAGE.

Application filed August 25, 1911.

To all whom it may concern: 7

Be it known that I, Lnwrs L. TATUM, a

citizen of the United States, residing at- Milwaukee, in the county ofMilwaukee and State of \Visconsin, have invented new and usefulImprovements in Pressure-Gages, of which the following is a full, clear,(30110186, and exact "description, reference belng had to theaccompanying drawing, forming a part of this specification.

My invention relates to improvements 1n. pressure gages and moreparticularly to gages in which contacts are prov ded to be engaged bythe pressure indicating needle for controlling electric circuits.

It is one of theobjects of my invention to somount the contacts to beengaged by the pressure needle as to permit the .dial plate to beprovided with an opening of sufficient size to enable full inspection ofthe gage movement without the removal of any-of the parts thereof.

A further object of my invention 1s to provide simple, durable'andeasily adjustable means for supporting the contacts to be engaged by thepressure indicating needle.

-Various other objects and advantages of my invention will behereinafter clearly and fully set forth.

For the purpose of disclosing the nature and characteristic features ofmy invention, I shall describe the gage illustrated in the accompanyingdrawing which embodies my invention in one form. It should be under- 3stood however, that my invention is'not lim' ited to the specific deviceillustrated, but is susceptible of various modifications.

In the accompanying drawings :Figure 1 is a front elevation of the gage;Fig. 2 is a view similar to Fig. 1 with the'cover and dial plateremoved. Fig. 3 is a sectional view taken on line 3-8 Fig. 1. Fig. i isa sectional'view taken on line 44 Fig. 2 and Fig. 5 is a side new of oneof the station i ary contacts and the ring carrying the same.

The gage selected for the purpose of illustration is provided with acasing of conventional form. The casing comprises a cylindrical boxmember 1 provided with an an nu ar supporting flange 2 and with a glasscover 3 retained in position by aring 4: threaded on to the portion 1.The gage movement including the pressure indicating needle 5 is mountedupon a metallic plate 6.

.' The gage movement is of conventional form Specification of LettersPatent.

Patented Dec. 1, 1914.

Serial No. 645,924.

and accordingly need not be specifically de scribed herein. The plate 6is in turn mounted upon an insulating supporting base 7, said base beingsuitably secured to and supported by the support 8' of the Bourdon tube9. Extending from the tube support 8 is the usual connection pipe 10.The tube 9 is preferably connected to the gage move ment through aninsulating-member ll. Vfith this arrangement it will be seen that thegage movement and tube are efiectually insulated from one another.

Suitably arranged within the casing is a dial plate 12. In practice thisdial plate may be secured in place in various difierent ways. I preferhowever to mount the same in a manner hereinafter set forth. The dialplate 12 is preferably of annular form with a central opening ofsuficient size to permit thorough inspection of the gage movementtherethrough. The dial plate is provided with the; usual graduated scale13 preferably stamped therein.

The dial plate 12 is preferably formed of insulating material and ofsuficient thick- A ness to permit of the formation of two annulargrooves 14 and .15 on the inner periphery thereof. The grooves M and 15are provided for the reception of expansion rings 16 and 17 respectivelywhich may be conveniently formed of resilient wire bent nto asubstantially circular form as shown in Fig. 5. In practice however, Iform each ring of somewhat larger diameter than itseorresponding grooveso that when placed in its groove lt will exert a pressure against thewalls thereof. This pressureWh-ich is largely augmented by pressureagainst either end of the wire forming the ring effectually holds thering against slipping in its groove. 0n the otherhand if the rings beslightly contracted as by drawing the ends thereof together they may bereadily slipped around or turned in their grooves. For facilitating thiscontraction of the rings the extremities18 of the wires forming the samemay be bent inwardly as shown in Fig. 5 so as to project out of thegrooves and thus be easily grasped.

The rings 16 and 17 are provided for the I prefer however, to make thesecontacts of 1 a cylindrical form and to mount the samev upon one of theextensions 18 of its supporting ring. Also i prefer to mount said con Igage needle and stationary contacts with silver engaging portions. Asillustrated I have shown the needle provided upon opposite sides of itsextremltv With circular sil-. ver contact tips 22 and the contacts 20and 21 with silver bands 23 encircling .the same.

With the rings, 16 and 17 mounted as above described in the insulatingdial plate, it is obvious that the same are thoroughly insulated fromone another and may be placed in close proximity Without danger. It Willalso be perfectly obvious that either of the contacts may be readilymoved to any desired position relative to the scale by merelycontracting and turning its-supporting ring, and that when the ring isreleased it will frictionally look its contact in the desired position.

The electrical; connections for the contacts andthe needle may be madein various Ways, but in practice I prefer to make them as follows :lprovide'on one side of the casing terminaldevices 25, 26 and 27. Theseterminal devices may be of any preferred construction. As illustratedeach comprises a bolt 28 passing through the casing and insulatedtherefrom by an insulating bushing 29 and insulating Washers 30 and-31.The bolt 28'carries at its outer'end a binding screw 32 for externalconnection, and at its inner end a conducting angle plate 33. The

middle terminal device 26 is intended for electrical connection to theplate 6 carrying the gage movement, this connection being made byaconducting strip 35 connected at one end to the angle plate 33 of theterminal device 26 and at its other end'to the plate 6.

The terminal devices25 'and 27 are intended for electrical connection tothe contacts 20 and 21 respectively. These connections are preferablymade through thin conducting strips 36 and 3? placed in the bottom ofthe grooves 1e and 15- respectively to be engaged by the rin s16 and 17respectively. The strips 36 an 37 preferably extend all the Wayaround'these grooves to insure good contact between the same and theirrespective rings in all positions of the latter. The

ment when the gage needle 5 engages contact 20 it connectsterminaldevices 25 and 23 and when it engages contact 21 connects terminaldevices 26 and 27.

Besides serving as electrical connections the angle plates 33 of theterminal devices 25 and 27 also serve as a convenient means of supportfor the dial plate. The dial plate may be readily secured to these angleplates as illustrated in Fi s. 3 and l by screws 40,

said screws also serving to secure the connecting pieces 38 and 39 otheir respective angle plates. In practice it is preferable to securethe dial plate at at least one more point, and for this purpose a lug-e1(Fig. 2) 1s formed inside of the casing, the dial plate being secured tothis lug by a screw 42 (Fig. l). lVhile this is the preferred Way ofsupporting the dial plate said plate may obviously be supported invarious other Ways.

What I claim as new and desire to scour by Letters Patent is as follows:

1. A pressure gage provided with an annular'dial plate, a pressureindicator movable tvithin the central opening of said dial plate andcontacts mounted upon the inner periphery of said dial plate'andprojecting into the path of said indicator to be engaged thereby in anabutting manner.

2;. A pressure gage provided with an annular dial plate, a pressureindicator, and

contacts adjustably mounted upon the inner periphery of said dial bysaid indicator.

A pressure gage provided with a corn taot' supporting member hatingannular grooves therein, expansion rings Within said grooves forfrictionally engaging the Walls thereof, and contacts carried by saidrings.

4. A pressure gage provided with a dial plate, a pivoted pressureindicator, said'dial plate having annular grooves therein concentricWiththe pivot of said indicator, expansion rings mounted in said groovesto frictionally engage the Walls thereof, and contacts carried by saidrings to be engaged by said indicator and to be adjusted to differentpositions by rotation of said rings.

5; A pressure gage provided with a pivoted pressure indicator, anannular dial plate concentric with the axis or said indicator, revolublerings mounted side by side on the inner periphery of said plate, andcontacts carried by said rings to be engaged by said indicator.

6. A pressure gage provided with a pivoted pressure indicator, anannular dial plate concentric with the axis of said indiplate to beengaged cator, revolublerings mounted side by side on the innerperiphery of said dial plate, and contacts carried by said rings to beengaged by said indicator, said rings tending to expand to frictionallyhold the same against movement.

7. In a pressure gage in combination, a

Eli

pivoted pressure indicator, an annular in.- dicating dial, said dialhaving a pair of parallel grooves on the inner periphery thereof,expansible rings mounted in the grooves in said dial plate, andcontactscarried by said rings to be engaged by said pressure indicator.

8. In a pressure gage in combination, an insulating dial plate having acentral opening for permitting full inspection of the gage movementWithout removal of any of the parts of the gage movement and contactsadjustably mounted upon said dial plate and disposed within said centralopen- 9. In a pressure gage incombination, an annular insulating dialplate having parallel annular grooves in the inner periphery thereof,conducting strips within said grooves, expansion rings Within saidgrooves and in contact with said conducting strips, and contacts carriedby said expansion rings to be engaged by a,moving part of the gagemovement.

10. In a pressure gage in combination, an annular insulating dial platehaving parallel annular grooves in the inner periphery one of saidterminal devices and between the conducting strips in said grooves andeither of said terminal devices.

11. A pressure gage provided with a pressure indicating device, anannular dial plate, members mounted upon the inner periphery of saiddial plate, said members being movable at Will around the innerperiphery of said plate and being self-locking, and contacts carried bysaid members to be engaged by said indicator.

In witness whereof, I have hereunto subscribed my name in the presenceof two Witnesses.

LEWIS L. TATUM. Witnesses:

FRArix H. HUBBARD, Gnoasn Harare,

